Four more Island estuaries are experiencing anoxic conditions and dead fish or shellfish have been found in some areas. Anoxia occurs when large amounts of decaying plant material such as sea lettuce use up the oxygen in the water.
Cindy Crane, surface water biologist with the Department of Environment, Energy and Forestry says the areas affected are the Suffolk branch of the Winter River at Tracadie Bay; upper Covehead Bay; Brackley Bay near Shaw’s Beach; and the Huntley branch of the Kildare River. In all cases, Ms. Crane said there is rotting sea lettuce and the water has turned a milky white or green colour and has a foul odour.
Department officials are also investigating a large mortality on an oyster lease in the Fox Island area of Mill River. While the river was not anoxic, Ms. Crane said the mortality may be the result of large mats of decaying vegetation lying on top of the oysters and smothering them.
Ms. Crane said there are more reports of severe anoxic events this summer than in recent years. She said conditions are always worse when there is a period of cloudy, rainy weather, followed by a period of intense heat as the Island has experienced this summer. Those weather conditions combined with wind and tide conditions to make this a particularly bad year for anoxia, Ms. Crane said.
Earlier this month, the Department of Environment, Energy and Forestry reported anoxic conditions in the Southwest River upstream of Long River; the upper Hunter River between Rusticoville and New Glasgow; the Wheatley River in the Oyster Bed area; and the Montague River near Dewar’s Point.
Ms. Crane said several hundred small dead fish, known as gudgeons, have been discovered by shellfishers in the upper Southwest River and by recreational fishers in a small tributary of the Hunter River. She said conditions in the Southwest River were slightly improved when readings were taken in the area last week. The department will continue to monitor the estuaries. Anoxic events are known to last from several days to a week or more, depending on weather conditions and prevailing tides.
To report an anoxic event, call the Department of Environment, Energy and Forestry at 368-5044 or toll free 1-866-368-5044.